That's right and that's why I said that it could only apply to Dugtrio in OU but the thing is that they can indeed trap and delete multiple mons in OU:
In the case of Diglett: Chansey, Kabutops, Infernape, Empoleon, Breloom, Tyranitar, Lucario, Weavile, Magnezone, Volcarona.
In the case of Trapinch: Kabutops, Empoleon, Infernape, Torkoal, Tyranitar, Lucario, Weavile, Magnezone, Excadrill, Darmanitan, Volcarona.
Those are some examples of mons that can be deleted at 100% if certain conditions are met, this of course doesn't change the fact that they would probably be pretty bad in OU and there would probably be no reason to use it other than to remove opposing Tyranitars. They will also need their Focus Sash in most cases to kill one of this mons.
It would be completely fine if their trapping ability only allowed them to trap some mons like Tyranitar and Magnezone so you can prepare for it but it clearly allows them to trap and delete more than that. They can even delete some mons after they have taken some damage. This is far from being something competitive. Even if something is bad it doesn't imply it can't be uncompetitive.